Relation of levels of dietary fat to atrial thrombosis in RF mice

Summary Massive atrial thrombosis developed in R F mice when fed a lipotropic-deficient diet containing either 40 %, 28 % or 6 % levels of lard as the fat. The protein content was 8 % casein. Carbohydrate (sucrose) levels of 45.5 %, 57.5 % and 79.5 % were used to balance the range in amount of fat. Within the 40 % fat group, 65 % of the mice developed atrial thrombosis as compared to a 36 % and 30 % incidence in the 28 % and 6 % fat level groups. The highest incidence of atrial lesions occurred during 10–12 weeks in the 6 % fat group, and during 18–22 weeks in mice fed the 28 % and 40 % fat levels. After feeding the diets for as long as 20 weeks the incidence of atrial thrombosis decreased rapidly in the 6 % and 28 % fat level groups. In contrast the incidence did not decline in the 40 % group until after 40 weeks.